Objectives: Design, develop, validate and market a low-cost, easy-to-use subjective refractor unit to quickly and accurately measure a patient's required vision correction in terms of sphere, cylinder and axis. Specific Aims: Establish the scientific merit and feasibility of the subjective refraction by meridional power matching technique by 1) designing an off-the-shelf SR-MPM using ZEMAX; 2) constructing and calibrating the SR-MPM breadboard; 3) developing software to generate patterns for display and convert SR-MPM outputs to a traditional refractive prescription; 4) determining the reproducibility of the SR-MPM; 5) comparing SR-MPM to traditional subjective refraction; 6) identifying design parameters needing optimization. Health Relatedness: The goal of the SR-MPM project is to provide low-cost accurate and quick measurements of a patient's required vision correction. Methods: Clinical applications of the SR-MPM will be defined and used to specify software and database requirements for Phase I. Optical system design will utilize optical engineering software. All software for the prototype will be developed and run on a PC. Test cases will be generated to validate the software implementation. Feasibility of the SR-MPM project will be evaluated per specified criteria. Technological Innovation: Providing an accurate, low-cost, low-maintenance refractor that can be easily transported and used in hostile environments. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE